Environment Minister Trevor Mallard has attacked the public relations woman who accused his predecessor David Parker of politicising the ministry, saying she was incompetent.
Erin Leigh, who worked at the ministry in 2006, has claimed Mr Parker pushed to get Labour Party member Clare Curran to be employed at the ministry to peddle his own personal agenda.
Ms Leigh said she was so angry at the appointment she resigned in protest before Ms Curran started.
Her boss also quit over Ms Curran's appointment, she said.
"David Parker wanted to ensure that his personal political agenda was being looked after," Ms Leigh said.
"Clare Curran was going to be there in a watchdog capacity and I felt from an ethical and professional perspective that I couldn't work in that environment so I resigned."
Under questioning in Parliament Mr Mallard turned on the former contractor.
"Erin Leigh had repeated competence issues. The piece of work that she was employed to do had to be fixed up six times by her after complaints from senior officials from a number of departments," Mr Mallard said.
"As a result of that someone had to come in and fix up the mess. Clare Curran was appointed to do that."
Mr Mallard said Ms Leigh had not been in the room when Ms Curran's employment was suggested.
He said no one who had been in the meeting had said Mr Parker directed her to be hired.
Mr Parker also said he did not direct the ministry to employ Ms Curran and Ms Leigh's claims were not correct.
Mr Parker said he had suggested Ms Curran's name to the ministry which had needed help in communicating climate change policy.
At the time the organisation was without a chief executive. Its head of climate change had also resigned.
"It was obvious that there was a need to change the way in which we were presenting these issues to the public because the 'fart' tax had failed, the carbon tax had been dropped, and we needed to change things."
National MP Gerry Brownlee claimed that after Ms Leigh resigned, Mr Parker's office had contacted her and tried to persuade her to stay and explained why he wanted Ms Curran in the ministry.
Mr Mallard responded by attacking her again.
"The last record of contact the ministry had with Erin Leigh was when she came in, in an agitated state, for quarter of an hour in order to clear out her desk.
"It is my understanding the last non-physical contact was when she sent an invoice to the ministry for that quarter of an hour."
Mr Mallard did not say whether Mr Parker's office had contacted Ms Leigh or not.
David Parker's spokeswoman said she did not know whether anyone contacted Ms Leigh and the inquiry would find out the facts of the matter.
Mr Mallard said there had been a breach in the process to employ Ms Curran in the tendering and contracting methods, but there had been no directions from the minister.
Ms Leigh said her boss Neal Cave also resigned over Ms Curran's appointment. Mr Cave has been described in ministry documents as responsible for information management.
Mr Mallard said he had heard no one else back up Ms Leigh's claim.
Ms Curran's contract at the ministry was never put out to tender. She was hired under its "exemption process", according to a State Service Commission report released on Tuesday .
Ms Curran was engaged for 200 hours work at $120 an hour for a contract that ran from May 22 to July 28, 2006.
The State Services Commission is holding an inquiry into National's claim of political interference in the ministry.
National had said Mr Parker should stand aside as State Services Minister until the inquiry is completed.
The SSC recently released another report into the sacking of Madeleine Setchell from the ministry after another Environment Minister, David Benson-Pope, said he could not work with her because her partner worked for National.